Meter for liquid



March 13, 1962 J. FAURE HERMAN METER FOR LIQUID Filed April 21, 1958United States Patent 3,024,656 METER FOR LIQUID Jean Faure Herman, 68Rue de lEst, Boulogne-sur-Seine, France Filed Apr. 21, 1958, Ser. No.729,871 Claims priority, application France Oct. 22, 1957 4 Claims. (Cl.73-230) Meters for liquid are already known comprising a turbine such asa screw revolving at a speed proportional to the volume of the flow ofthe liquid.

It is also known to provide these meters with means for causing anoutlet section of the nozzle of the turbine to vary as a function of thedensity of the liquid and various extrenal factors intervening on thevalue of this density such as temperature. This type of arrangementenables the speed of the turbine to be modified as a function of thedensity of the liquid, which enables the value of the aggregate flow ofthe liquid to be ascertained.

According to other known arragements, the turbine is placed in acone-shaped nozzle. Means are provided to ensure axial displacement ofthe turbine relative to the nozzle so as to regulate the section of thenozzle cooperative with the turbine corresponding to a valuerepresentative of the density of the liquid of which the aggregate flowrequires to be measured.

Again, according to other known characteristics the means for regulatingthe section of the nozzle of the turbine are, on the one hand,adjustable by hand as a function of the density of the liquid at areference temperature, and on the other hand, automatically as afunction of the temperature variation in relation to that of thereference temperature to allow for the variation in density of theliquid as a function of the temperature.

The present invention seeks to provide various improvements in manualcontrols ensuring the relative displacement of the turbine andcone-shaped nozzle along its longitudinal axis.

The invention also has the object of avoiding the thrust of the liquidon the cone-shaped nozzle and to ensure a correct distribution oflaminary speeds in the passage section of the fluid about the turbine.

A meter for liquid enabling the afore-mentioned objects to be achievedpossesses the characteristics which set out in the following descriptionand more particularly in the attached claims.

A meter for liquid according to the invention is shown by way of examplein the attached drawings, in which:

FIG. 1, is a cross-section elevation view of an embodiment of the meterfor liquid according to the invention.

FIG. 2, is a diagram of an embodiment of remote control mechanism fordisplacing the cone-shaped nozzle of the meter, illustrated in FIG. 1,to the variation in density of the fluid whose aggregate flow isrequired to be measured.

A meter for liquid shown in FIG. 1 consists of a meter body member 1connectable in a fluid channel or conduit and having an inlet and anoutlet. A cone-shaped nozzle 3 is placed in this body, and can be movedaxially along its longitudinal axis. The nozzle has a passageway with aninlet and diverging outlet for allowing fluid flow therethrough andthrough the meter.

A turbine row comprising a screw 4 revolves freely around the spindle 5at a position fixed in relation to the meter 1 and is driveable by theliquid flowing through the meter.

By shifting the cone-shaped nozzle 3 the diameter can be varied of thepassage section in which the screw 4 rotates.

The movement of the nozzle 3 is controlled by a rod 6 I 7 disposedtransversely of the nozzle 3. This rod has one end extending externallyof the meter body 1 and is provided with a screwdriver slot 7.

The other or inner end of the rod 6 carries a pinion 8 meshed with arack element 9 integral with the nozzle 3. An external nut 11 whichcooperates with a threaded portion of the rod 6 permits locking thenozzle in the position obtained after the axial adjustment thereof.Plastic rings 12 ensure tightness during the adjusting operation, thenut 11 being then loosened.

This arrangement affords several advantages. More particularly, itenables the meter to be calibrated in a very handy manner, seeing thatit is no longer necessary for this calibration operation to re-machine,during testing, the diameter of the passage section in which the screwis disposed, in order to obtain sufiicient accuracy of the elementarymetering volume.

The rod 6 can be rotatively driven manually by means of a screwdriver orby a servomotor.

This arrangement enables the positioning of the axial movable nozzle byrack and pinion which, on the one hand, allows a meter to be usedgraduated by weight, without automatic correcting mechanism and settingmanually compensation for nominal densities of the liquids in the casewhere this density remains constant during metering.

According to the invention a tubular throttle member 13 is fixedupstream of the nozzle axially spaced therefrom. This throttle memberconcentrates the fluid jet towards the entrance to the nozzle, thuscreating an annular zone 14 in which a pressure drop takes place andcounter-balances the thrust on the nozzle 3. By varying the diameter ofthe throttle member 13, this acts on the value of the pressure drop ofthe zone 14, and at the same time on the speed and peripheral pressureof the liquid in the nozzle 3.

Thus, this entry throttle member, placed at a certain axial distanceupstream of the cone-shaped nozzle 3 and with a reduced diameterslightly smaller than that of the small entry section of the latterdownstream of the entry thereof, enables, on the one hand, a reducedpressure zone to be created neutralizing the thrust of the liquid on thecone-shaped nozzle 3, and on the other hand, to effect a variation inthe distribution of laminary speeds in the passage section to rendersubstantially uniform the velocity of the liquid in any cross section ofthe liquid flowing therethrough at any one time and thus to make themeter accurate within a range of liquid output readings.

The liquid meter according to the invention also comprises a deviceaffording remote control, in the case of a variable density of theliquid. The device positions the cone-shaped nozzle 3 according tothermometer readings or directly in response to density sensing meanssuch as a densimeter, placed at any point in the liquid circuitpreferably upstream of the meter, by means of an electric transmissionacting on a servo-motor.

To this end, FIG. 2, a reversible servomotor 16 directly engages the rod6 of the driving pinion 8. The rotor of the motor 30 is integral withthe slider 17 of a potentiometer 18 mounted as a Wheatstone bridge witha potentiometer 19. The slider 20 of the potentiometer 19 is directlyconnected to the position, for example, of the float of a densimeter 21.The electric motor 16 is connected to one of the diagonals of theWheatstone bridge. The other diagonal has an electric source 23connected therein. In these conditions, the rotor of the motor 16, andconsequently, of the nozzle 3, is always stabilized in a positioncorresponding to that where the sliders of the potentiometers 18 and 19balance the Wheatstone bridge. Owing to this face, the movements of thenozzle 3 are governed by those of the float of the densimeter 21.

The density sensing means 21 varies the ratio of one pair of arms of thebridge relative to the other pair of arms in response to density changesin the liquid. The servomotor moves the nozzle 3 to axial positionscorresponding to balanced conditions in the bridge circuit, establishedby the servomotor so that continuous automatic compensation for densitychanges is provided and the liquid meter is accurate regardless ofdensity changes.

What I claim is:

1. A liquid meter for measuring the volume of liquid passing through themeter comprising, a body member having an inlet and an outlet, a nozzlemember disposed axially in said body member having a passageway providedwith an inlet and a diverging outlet for allowing liquid flowtherethrough, a turbine rotor disposed in said passageway in the nozzlemember driveable by liquid flowing through the nozzle member, means forautomatically displacing the nozzle member axially relative to theturbine rotor to compensate for changes in density of the liquid flowingthrough the meter comprising, a Wheatstone bridge comprising a parallelcircuit having two pairs of arms, means for sensing density changes inthe liquid upstream of the nozzle member connected to said Wheatstonebridge circuit to vary the ratio of one pair of arms relative to theother pair of arms, a reversible servomotor connected to said bridgecircuit operably connected to said nozzle for displacing it axiallyrelative to said turbine rotor in response to unbalanced conditions insaid bridge circuit caused by said density sensing means and connectedto the bridge circuit to position the nozzle member in positionscorresponding to balanced conditions in said bridge circuit, and meanscooperative with the motor and Wheatstone bridge circuit for causing themotor to position said nozzle member in said position corresponding to abalanced condition in said bridge circuit and to cause the motor to movesaid nozzle member axially in one of two opposite directions independence upon the unbalanced condition established in said bridgecircuit by said density sensing means.

2. A liquid meter for measuring the volume of liquid passing through themeter comprising, a body member having an inlet and an outlet, a nozzlemember disposed axially in said body member having a passageway providedwith an inlet and a diverging outlet for allowing liquid flowtherethrough, a turbine rotor disposed in said passageway in the nozzlemember driveable by liquid flowing through the nozzle member, means forautomatically displacing the nozzle member axially relative to theturbine rotor to compensate for changes in density of the liquid flowingthrough the meter comprising, a Wheatstone bridge comprising a parallelcircuit having two pairs of arms, means for sensing density changes inthe liquid upstream of the nozzle member connected to said Wheatstonebridge circuit to vary the ratio of one pair of arms relative to theother pair of arms, a reversible servomotor connected to said bridgecircuit operably connected to said nozzle for displacing it axiallyrelative to said turbine rotor in response to unbalanced conditions insaid bridge circuit caused by said density sensing means and connectedto the bridge circuit to position the nozzle member in positionscorresponding to balanced conditions in said bridge circuit, meanscooperative with the motor and Wheatstone bridge circuit for causing themotor to position said nozzle member in said position corresponding to abalanced condition in said bridge circuit and to cause the motor to movesaid nozzle member axially in one of two opposite directions independence upon the unbalanced condition established in said bridgecircuit by said density sensing means, and a tubular throttle memberdisposed upstream of said nozzle member axially spaced therefrom andhaving an inlet and outlet opening to allow fluid flow therethroughthereby to create a zone of reduced liquid pressure in a space betweensaid nozzle member and said throttle member to compensate for axialthrust on said nozzle member.

3. A liquid meter for measuring the volume of liquid passing through themeter comprising, a body member having an inlet and an outlet, a nozzlemember disposed axially in said body member having a passageway providedwith an inlet and a diverging outlet for allowing liquid flowtherethrough, a turbine rotor disposed in said passageway in the nozzlemember driveable by liquid flowing through the nozzle member, means forautomatically displacing the nozzle member axially relative to theturbine rotor to compensate for changes in density of the liquid flowingthrough the meter comprising, a Wheatstone bridge comprising a parallelcircuit having two pairs of arms, means for sensing density changes inthe liquid upstream of the nozzle member connected to said Wheatstonebridge circuit to vary the ratio of one pair of arms relative to theother pair of arms, a reversible servomotor connected to said bridgecircuit operably connected to said nozzle for displacing it axiallyrelative to said turbine rotor in response to unbalanced conditions insaid bridge circuit caused by said density sensing means and connectedto the bridge circuit to position the nozzle member in positionscorresponding to balanced conditions in said bridge circuit, meanscooperative with the motor and Wheatstone bridge circuit for causing themotor to position said nozzle member in said position corresponding to abalanced condition in said bridge circuit and to cause the motor to movesaid nozzle member axially in one of two opposite directions independence upon the unbalanced condition established in said bridgecircuit by said density sensing means, a tubular throttle memberdisposed upstream of said nozzle member axially spaced therefrom andhaving an inlet and outlet opening to allow liquid flow therethrough,said throttle member having an internal reduced diameter downstream ofsaid inlet opening thereby to render substantially uniform the velocityof the liquid in any cross section of the liquid flowing therethrough atany one time so as to render the meter more accurate within a range ofliquid output readings, and said reduced internal diameter beingsubstantially equal to an internal diameter of the nozzle memberdownstream of its inlet and adjacent thereto.

4. A liquid meter for measuring the volume of liquid passing through themeter comprising, a body member having an inlet and an outlet, a nozzlemember disposed axially in said body member having a passageway providedwith an inlet and a diverging outlet for allowing liquid flowtherethrough, a turbine rotor disposed in said passageway in the nozzledriveable by liquid flowing through the nozzle, means for automaticallydisplacing the nozzle axially relative to the turbine rotor tocompensate for changes in density of the liquid flowing through themeter nozzle including means for sensing density changes in the liquidupstream of the nozzle, a tubular throttle member disposed upstream ofsaid nozzle member axially spaced therefrom and having an inlet andoutlet opening to allow liquid flow therethrough, said throttle memberhaving an internal reduced diameter downstream of said inlet openingthereby to render substantially uniform the velocity of the liquid inany cross section of the liquid flowing therethrough at any one time soas to render the meter more accurate within a range of liquid outputreadings, and said reduced internal diameter being substantially equalto an internal diameter of the nozzle member downstream of its inlet andadjacent thereto.

References Cited in the file of this patent UNITED STATES PATENTS2,240,119 Montgomery et al. Apr. 29, 1944 2,820,364 Bevins et al. Jan.2l, 1958 FOREIGN PATENTS 1,108,314 France Aug. 24, 1955

